This invention relates to a process for preparing a polymeric oxime and to the polymeric oxime of such process. More particularly, it relates to a process for preparing a polymeric oxime especially adapted to utilization in photographic processing compositions.
Polymeric oximes and their preparation and utilization as viscosity-increasing reagents in photographic processing compositions have been described in U.S. Pat. No. 4,202,694 (issued May 13, 1980 to L. D. Taylor). In the conduct of, for example, photographic diffusion transfer processes, it has been conventional practice to effect development with the aid of a processing composition which includes a viscosity increasing reagent to facilitate uniform application of the processing composition to an exposed film unit. In the aforesaid patent, polymeric materials having pendant oxime groups, and inclusive of such materials as poly(diacetone acrylamide oxime), are described as especially adapted to utilization as viscosity-increasing agents in photographic processing compositions. While the polymeric oximes of the aforesaid patent provide advantageous properties in photographic processing compositions, particular and useful properties thereof may in part be determined by the particular process utilized for the production of the polymeric oxime.
In the processing of a diffusion transfer film unit where a processing composition is typically spread from a rupturable container by passage of the film unit between a pair of rollers so as to distribute the processing composition between sheet elements of the film unit, it is desirable that the coverage or amount of processing composition spread between the elements be substantially uniform over a range of processing temperatures. Inasmuch as appreciable variation in processing composition coverage can affect development, opacification and other photographic functions, it is especially advantageous that a photographic processing composition be susceptible of use in diffusion transfer processing while providing considerable processing temperature latitude, i.e., that the processing composition be capable of being spread with substantial uniformity over a wide range of processing temperatures.